bourcier de carbon



Aug. 18, 1959 c. M. L. L. BOURCIER DE CARBON 2,399,635

RESILIENT STILTS Filed. Nov. 8, 1955 INVENTOR a W a who BY 6 a4 M y yamATTORNEYS Unite 1 States Patent D 2,899,685 RESILIENT STILTS"ChristianM. L. L.-B'ourcier de carbon, Neuilly-sur-Seiue, France.

Application November 8, 1955, SrialjNb. 545,670

2 Claims. (Cl. 3 --4) This invention relates to' resilient stilts andhas for its general object the provision of novel andimproved re silientor elastic stilts which involve the use ofpneumatic cushioning devices.

Caricaturists and humoristshave already dreamed of arranging coilsprings, that is to say, metal helical springs, under the sole of theshoes of imaginary: personages so as to thus constitute a kind ofportable springboard, making it possible to eifect spectacular jumps,for example to jump over the roofsof houses. In this simple form, thisidea actually constitutesonly a Utopian dream -and this for severalreasons:

(1) In order to jump to a certain height simply because of the elasticstrengthof the spring, it-is necessary to have a sufficiently longstroke of spring. Under such conditions of length, a coil spring wouldnot be laterally stable and would become deformed in all directions,giving rise to the well-known phenomenon-of buckling when one would tryto makeit work.

(2) In order to permit the making of appreciable jumps, that is to say,in order for a man to jump to a-certa-in height, the spring would haveto be able to store a corresponding quantityof power, that is to say, a'considerable number of kilogram-meters. Now. ametal spring can storewithout breakage, only a comparatively small quan tity of kilogrammeters, perkilogramof metal. If one calculates the order of magnitude,-one-easily realizes that inorder to make jumps of considerable height,it would be necessary toplace under each foot some rather heavy springsand therefore, it would be very uncomfortable.

In the over-simplified-formof a metal coil spring, the elastic sole istherefore. only a.hurnorous idea of Utopian quality, without anypractical interest; because it constitutes a contradiction with theactual propertiesof. matter and in particular, the properties. of metalsprings. However, this Utopian idea, provided. that it is assisted by asuitable technical analysis, may be considered as containing latently,the germ of one of the most curious inventions, namely, the pneumaticstilt, and actual sevenleague boot.

From the preceding analysis, it results as a matter of fact that ajumping skate or a portable jumping board must, first of all, complywith the following two conditions:

(1) It must permit a rather long expansion stroke, vertically, and astroke as large as possible.

(2) It must allow the sole to move only longitudinally in the directionof the leg and it must absolutely prevent any transverse displacement.

These two absolute requirements can be complied with and this is thefirst aspect of the present inventionby making the jumping apparatus inthe form of a stilt with an elastic leg.

Other objects and features of novelty will be apparent from thefollowing specification, when read in connection with the accompanyingdrawings in which one embodiment of the invention is illustrated by wayof example.

In the drawings:

2; Figure 1 is -a view inelevation of a stilt having elastic or springsupporting means; and

Figure 2 is avertic-al sectional view of a pneumatic device-which isused in providing a-pneumaticallyssupe ported stilt inaccordance withthe invention.

Referring to Figure 1', the invention essentially'consists of a stiltconsisting of two parts:

(1) A framework A which is substantially rigid with the leg]- (Figure 1)and, for example, is fastened to -the latter on the one hand by astirrup E' on which the foot willrest or by'any other equivalentfasteningsystem, and on the other hand, by 'a beltF tightly secured-tothe leg below the knee.

(2') A vertical rod T which is-rigid' and is arranged so as'to extendbeyond the leg as in the conventional-stilt, is so mounted as to becapableof sliding in the'-frame work A and is elastically connected'with this framework, so as toflex' to a" greater or lesser extent underthe load like a' spring.

The core of this elastic connection could be a metal spring; forexample;acoil spring which would" have the drawback already pointed out of beingrather heavy.

In. order to reduce the weight, one could use a-rubber spring, suchaspring making it possible to store agreater amounttofienergy for thesame-mass ofmatter. Such a rubberspring could be made, for example, by aribbon or tape R; Figure 1, or a ring or a series of rubber rings.

However, the spring-which for a given weight makes lit possible: to"store-the greatesrquantity of mechanic-al energy, is the pneumaticspring: The preferred formor shape of" the elastic'stiltis therefore thepneumatic stilt and" this also is oneofthe most important-aspects of thepresent invention.

Such a pneumaticstil-t isessentia'lly constituted on the onehandbycylinder C, Figure 2,;closed at its upper. end, this cylinder playingthe part of the framework A ofFigme 11, anion theotherhand by acylindrical rodB (corresponding to partT in Figure l)'which slidesin-cylind'er C and protrudes partly outside ofthe latter, thesetwomembers movable-With respect'toeach other; thus constituting an innerreceptacle" ofvariable volume due to the packing D calri'ed on the lowerpart of cylinder. C.

Also, the cylinder C is provided with an inflatingval've V' making itpossible to inject inside the said receptacle air under pressure so. asto: extend-the rod 3 outwardly thus. constituting a veritable pneumaticspring. Therod B may besolid'but shouldpreferably be tubular-as shown inFigure 2".

Furthermore, in order to assure the guiding-of" the cylindrical rod B,the latter may be provided'at its upper part with ailange orpseudo-piston P, sliding-without any appreciable play inside thecylinder C and perforated with openings 0 so as to provide relativelyunrestricted communication between the receptacles M and N. The wholerod and flange assembly constitutes a plunger member having a sealed orpacked sliding relation with the cylinder member, and is of a volumewhich causes an appreciably increased compression of the compressiblefluid in the cylinder when the two members are telescoped and successiveincrements of the plunger enter the cylinders.

Furthermore, also, a few cc. of oil could be injected above the packinggasket D so as to lubricate the gasket.

The pneumatic stilt which is the subject matter of the present inventionwill make it possible to make very spectacular jumps because it willoperate like a portable jumping board which is perfectly elastic and thereaction force and the extension stroke of which may be as great asdesired. The sole loss of energy or power at each The elastic stilt mayalso be used to improve the performances in running races and walkingtheessential reason being that the speed of man on his own legs is verylimited and is especially fatiguing so that running is nothing but asuccession of leaps and at each leap, the energy of the verticalcomponent of motion must first of all be entirely destroyed due to thenegative muscular work (negative work which also causes as much fatigueas positive work as is well known by all those who traveled longstretches down mountains), before it is again reconstituted by positivework of the same muscle. This is the essential reason why the energyyield when running races is very low and this is also Why performancesin racing remain very limited even when the slope favors the run becausein such a case althoughthe positive muscular work is reduced, this isalmost compensated from the point of view of fatigue by the increase innegative work which absorbs power or energy and which also createsfatigue.

This poor yield of power in running explains why a man on a bicycle canmove more rapidly with less fatigue by simply using his muscular energyin spite of the resistance to the rolling of the tire on the ground,which resistance is not negligible. The elastic stilt operatesparticularly without any dissipation of energy, the energy of the fallnot being destroyed but only stored and made available for the nextjump. The use of elastic stilts will, therefore, permit man to walk orto run much faster and with much less fatigue. The progress in thisfield will probably be comparable to that obtained by the use of abicycle, with the advantage of being able to jump without any difficultyabove obstacles and of being able to use any ground provided that it issufliciently firm, while a bicycle demands ground which must be preparedfor this purpose and in practice, cannot be used except on roads andhighways.

Actually, there is concerned in this connection an entirely novel sportof many varied aspects which will enable the user of the stilt, thanksto displacement in three dimensions, to experience an entirely novelsensation which might be termed that of semi-flight. This is the dreamof the seven-league boot finally made into a reality due to a rationaltechnical analysis.

However, the more spectacular and more sensational aspect of this newmode of locomotion is that of a novel down-hill sport which could be toa certain extent compared with skiing. As a matter of fact, the reasonwhy skiing, and in particular mountain skiing, is so successful, isbecause of the sensation of space and of motion and even one could sayof trajectory which it permits its fans to experience. It is obviousthat sensations of this kind and perhaps even more intense than thoseexperienced when simply sliding on skis can be expected from this newsport if it is considered as a down-slope sport. As a matter of fact, itwill be possible to make jumps of considerable magnitude very easily andalmost without fatigue, inasmuch as the necessary energy isautomatically supplied at each jump or leap as a result of thediflerence in levels.

In order to make it possible to retain ones equilibrium, it will beadvantageous to practice this downhill sport with a supporting stick ineach hand as is done when skiing, and this, furthermore, increases thesimilarity between the two sports. Finally, the same means forreascending mechanically which are used in winter for skiing could beused in summer for this new down-hill sport.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

l. A jumping device particularly for sport use comprising a hollowcylinder closed at the top, a plunger rod entering the cylinder throughthe lower end thereof and adapted to reciprocate therein, an airtightsealing packing at the lower end of the cylinder through which theplunger rod passes, the lower end of said plunger rod comprising theground contacting portion of the device, a supply of gas under pressurein said cylinder, said plunger having at its upper end portion a flange,the peripheral margin of which is in free sliding contact with the innerwall of the cylinder for the purpose of axial guidance only, the flangebeing provided with openings large enough for the free passage of gastherethrough so as to place the space in the cylinder above the flangeand the space beneath the flange between the flange and said packing andsurrounding the plunger in free communication with each other.

2. The jumping device as set forth in claim 1 in which the plungermember is hollow, having a closed lower outer end and having an openupper inner end communicating with the compressed air-filled interior ofthe cylinder, thus serving to increase the volume of compressed airwithin the system, and in which the cylinder is provided with means forsecuring it to one of the lower limbs of the user.

References Cited in the file of this patent UNITED STATES PATENTS675,912 Wenneborg June 11, 1901 767,008 Pelletier et al Aug. 9, 19041,545,437 Malone et al July 7, 1925 1,575,847 King et al. Mar. 9, 19262,068,578 Stronach Ian. 19, 1937 2,783,997 Gaffney Mar. 5, 1957 FOREIGNPATENTS 353,119 Germany Dec. 28, 1920 650,009 Great Britain Feb. 7, 195168,709 Netherlands Sept. 15, 1951

